Stored biological samples in biorepositories are an important resource for research into the diagnosis and etiology of diseases. Biological specimens are stored in military facilities, forensic DNA banks, government laboratories, diagnostic pathology and cytology laboratories, commercial enterprises, and nonprofit organizations such as hospitals. Preservation and analysis of biological samples increases knowledge about diseases and provides a basis for developing better processes to prevent, diagnose, and treat these diseases.
A conservative estimate shows that 282 million specimens are currently stored in U.S. facilities, and the rate has been increasing at 20 million specimens per year beginning since 1998 (National Bioethics Advisory Commission, “Research Involving Human Biological Materials: Ethical Issues and Policy Guidance”, Volume 1 Report and Recommendations of the National Bioethics Advisory Commission, Rockville, Md., August 1999). Specimens are stored as slides, paraffin blocks, formalin-fixed, tissue cultures, or extracted DNA. Research in fields such as cancer, infectious diseases, and mental disorders is advanced by quick access to such materials.
Biological samples are typically stored frozen, for example at about −20° C., −40° C., or at about −80° C. in cryotubes. Current industry methods of aliquotting samples involve thawing and refreezing the storage volume of the specimen each time an aliquot is removed. Laboratory results indicate that repeated freeze-thaw cycles degrade the specimen. However, freezing (cryostorage) extends the usable life of biological samples.
Further, current methods for accessing and processing samples involve delay and are a bottleneck in the use of these repositories. The sample is exposed to repeated freeze/thaw cycles that degrade the sample. Alternatively, storage of one specimen divided into multiple containers prior to freezing results in the inefficient use of freezer space and potential increased costs of cryotubes, labels, and time, and introduces a new source of error in processing.
An efficient method for obtaining samples (aliquots) from frozen biological specimen from storage volumes, i.e., reducing the need for excess freezer storage space, reducing lead-times for receiving specimens, and reducing degradation of specimens is needed.